What is REM on an Amp?

Norvan Martin
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This question might be quite simple if you are a car engineer, computer geek, or a random tech professional. However, to a tech newbie, this could be a million-dollar question, so we will try to explain the concept in the most basic form possible. Therefore, by the end of this article, you will understand the concept of REM, its function, and why it is important in an amplifier.

What is REM?

REM means remote or Remote Amp turn-on and is a 12V BLUE wire (with no stripe) that comes directly from your head unit and is used to turn on the amp from a head unit. When an amp is connected to power, it will not turn on until a signal comes on the remote wire. You can connect the rem wire to either the remote trigger of the Head Unit (deck) or go to your fuse box and use the IGN or ACC fuse.

If connected to the head unit, the remote wire will be used to turn on the amp from the headunit. However, when connected to the IGN, the amp will power on when the vehicle turns on. You can also connect the rem wire to the fuse box, check out this guide to learn more.

Now, this may be easy to be confused about something else (say, a remote control for playing songs, changing the channel, and so on).

But in its most basic form, the REM wire on the amplifier functions as the power trigger. It is a button that tells the device to play, something like a command that tells the device when to start after it has been plugged in.

What is REM On An Amp?

To make it a lot easier, think of an amplifier like your regular TV set. You can plug the power cable into an electrical socket but it won’t come on until you press the power button (either on the TV or its remote).

Connect rem wire to headunit

Just like the power button on that TV, REM is the power trigger on an Amp. Before an amp can begin its full function, it needs something to trigger it when it is connected to a power source. 

In most common ways, to set up the REM properly, you will need to splice the wire in the head unit (i.e. the deck) into the remote trigger.

Another method to set it up will be to push the remote-on wire into the ACC or IGN fuse with the small fuse in the fuse box. A simple way to confirm the REM in an amp is active is if the stereo device comes on with the ignition turned on.

What is REM On a Subwoofer?

Rem means remote amp on a subwoofer. Just As it has been explained in the previous sections, it is the trigger that powers the amp when the ignition is turned on.

In a basic lineup, the subwoofer is directly (passive sub) or indirectly (active sub) connected to the amplifier. And, since the REM turns the amp on, it is also directly or indirectly responsible for turning the subwoofer on.


How To Connect REM In An Amplifier

The first thing to note about connecting REM to an amplifier is that a stock amp connection will differ from an aftermarket amp. Stock amps don’t come with any wire, whereas aftermarket amps have wires on them already, and this includes the remote-on wire.

Stock Head Unit Connection

Remember, this does not come with a remote-on wire. There you need to get this wire which is connected from the amplifier to either a fuse box, a 12V switch source in the car, or the power antenna wire.

Here is the step-by-step approach to connecting it to the fuse box, since it is the simplest and probably the fastest method to get power to the amp.

  • Start by turning off the ignition button.
  • Connect the remote wire to the amplifier and run it to the fuse box for power.
  • Locate a suitable spot on the fuse box. Any spot will be fine as long as it can supply power to the remote-on wire when the ignition is turned on.
  • This step is to be sure that the spot you have chosen on the fuse box will send power to the amp. Use a voltmeter to test this spot. If you get 12v on turning the ignition on and 0v when turned off, it means that the spot is good.

Aftermarket Head Unit Connection

Typically, on most aftermarket amplifiers, the remote-on wire is usually blue with a white wire. The remote-on wire is usually behind the car stereo where you can easily access it. Here are a few steps to connect the remote-on wire to an amp for the aftermarket head unit.

  • The aftermarket amp has a wiring harness with blue and white wire. Simply connect the blue wire in this harness to another line of primary blue wire. After that, run the primary wire that has been connected back to the amp in a way that ends the primary wire in the remote wire terminal. 
  • The second method is just a completion of the first, and this is the protection of the spliced wire. Ensure to solder the splice wire and protect it with a heat shrink.

What is REM Out On a Car Stereo?

The car stereo has a sensor that is also the remote on output. This means that when you turn on the radio, it automatically receives an audio signal and in response to this, it sends out a 12V signal to the amplifier. This signal is sent through the remote output wire, which is connected to the amplifier.

REM Ground 12v

Ground 12V is a common slang among tech geeks to refer to the nominal battery volt for connecting the REM. This is the negative ground system that is passed out from the negative terminal. It is mostly securely mounted on bare metal.

The remote ground 12v is the negative power from the head unit and it is mostly mounted close to the stereo.

Where Does The Rem Wire Connect To?

The remote turn-on wire is low current, so it can be connected to almost any of the fuse terminals. However, the remote turn-on wire by common practice connects to two places for effective function.

The first is the amplifier which carries out the function of triggering the one-and-off. Second, it connects to a power source. This could be the head unit, a fuse box, an ACC wire, an antenna module, or a turn-on module. This is to supply the power needed to trigger the amplifier.

How To Turn On The Amp Without A Remote Wire

There are many methods you can use to achieve the same result, but any method you choose to go with will depend on how the amp is designed.

The 2 popular methods for turning an amp on without using a wired connection include using a remote control or using a trigger/power button that comes with the amp.

The first way to easily turn on your amp without a remote wire is if your amp has a remote control. Most modern amps these days come with a remote control, which makes it easy to use the amp independent of the car’s ignition.

Another method is if the amp is designed with a power button that you can simply use to power it on and off. However, this can be stressful since you will have to reach towards it every time to turn it on and off.

How To Turn On an Amp Without the Remote Wire?

It is possible to turn on an amp even if there’s no remote wire. You could make it happen with a remote control or by pressing the on/off switch that comes with the amp itself.

If your amp comes with a remote, it’s pretty easy to turn it on or off. Many new amps come with remotes, making them easy to use.

If you don’t have a remote, that is no issue. You can also hit the power button on the amp to get it going or shut it down. Sure, you’ve got to be right there by the amp to do it, but it works all the same.


The remote-on wire, also known as REM wire, functions as a powerful trigger for turning on and off the amplifier when the stereo is not in use. This method saves you from the stress of turning the Amp on and off manually every time you need to use it. We hope this article helps you understand the concept of REM and answers all your questions about it.

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Norvan Martin is the founder of BoomSpeaker.com. He is a professional Electronics Engineer and is passionate about home theater systems and AV electronics. BoomSpeaker was created as an online hub to share his knowledge and experiences as it relates to home theaters and home audio electronics. My email: [email protected]  Connect on Pinterest and Linkedin